/*
 * Copyright 1999-2020 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.nacos.naming.healthcheck.v2.processor;

import com.alibaba.nacos.naming.core.v2.metadata.ClusterMetadata;
import com.alibaba.nacos.naming.core.v2.pojo.Service;
import com.alibaba.nacos.naming.healthcheck.v2.HealthCheckTaskV2;

/**
 * 健康检查机制
 *
 * 心跳机制仅仅是临时实例用来保护的机制，而对于永久实例来说，一般来说无法主动上报心跳，就比如说 MySQL 实例，肯定是不会主动上报心跳到 Nacos 的，所以这就导致无法通过心跳机制来保活
 * 所以针永久实例的情况，Nacos 通过一种叫做健康检查的机制区判断服务实例是否活着
 * 健康检查跟心跳机制刚好相反，心跳机制是服务实例向服务端发送请求
 * 而所谓的健康检查就是服务端主动向服务实例发送请求，去探测服务实例是否活着
 *
 * 一般来说分为三种方式
 * TCP
 * HTTP
 * MySQL
 *
 *
 * Health check processor for v2.x.
 *
 * @author nkorange
 */
public interface HealthCheckProcessorV2 {
    
    /**
     * Nacos 服务端会去创建一个健康检查任务
     *
     * Run check task for service.
     *
     * @param task     health check task v2
     * @param service  service of current process
     * @param metadata cluster metadata of current process
     */
    void process(HealthCheckTaskV2 task, Service service, ClusterMetadata metadata);
    
    /**
     * Get check task type, refer to enum HealthCheckType.
     *
     * @return check type
     */
    String getType();
}
